Rapid cure carbohydrate composition

ABSTRACT

A curable binder composition consisting essentially of one or more ammonium salt of an inorganic acid and at least one carbohydrate, and the use thereof as a thermosetting binder. Also described are composite materials comprising the curable binder composition, and methods of application.

This application claims the benefit of priority under 35 U.S.C. 119 (e)of U.S. Provisional Patent Application Ser. No. 61/208,736 filed on Feb.27, 2009.

This invention is a carbohydrate curable composition useful as athermosetting binder for a variety of applications. More particularly,the present invention relates to aqueous binder compositions comprisingone or more ammonium salt of an inorganic acid and at least onecarbohydrate, and the use thereof as curable binders.

Due to their favorable cost/performance ratio, the thermosetting binderresins of choice in the past have been phenol/formaldehyde orurea/formaldehyde resins. However, curable compositions containinglittle or no formaldehyde are now highly desirable in a variety ofproducts, due to the health and environmental problems associated withformaldehyde. Applications for formaldehyde resins are extensive. Theseinclude coatings, adhesives, carbonless copy paper, molding compounds,bonded and coated abrasives, friction materials, foundry resins,laminates, air and oil filters, wood bonding, fiber bonding, composites,spherical fillers, and fibers. These fibers may be cellulosic, polymericsuch as polyester, or mineral fibers. The mineral fibers may consist ofmolten glass, slag or stonewool. Typically these fibers are blown into aforming chamber, sprayed with a binder, and deposited as a web on to aconveyer. The coated mineral fibers are drawn into a curing oven andshaped into various building and insulation products. In the case ofinsulation products, cured mineral fiber binders allow the insulation tobe compressed, but have rigidity that allows the compressed insulationto recover substantially to its original shape once compressive forcesare removed. This allows, for example, the insulation to be shipped in arolled, compressed state and unrolled before installation to release thecompression, and allow a fluffy, heat-insulating mat to be installed.Existing commercial formaldehyde-free binders most commonly contain apolycarboxylic acid polymer and a polyol that esterify and form athermoset when heat cured. However, these binders are known to bederived primarily from petroleum feed stocks which are dwindling andexperiencing wide price fluctuations. Formaldehyde-free binders derivedfrom alternative feed-stocks are desired.

One alternative to petroleum is described in International PatentPublication No. WO 2007/014236, which discloses binders to produce orpromote cohesion in non or loosely assembled matter comprising an aminecomponent, which is either a protein, a peptide, an amino acid, or anammonium salt of a polycarboxylic reactant in combination with areducing sugar or non-carbohydrate carbonyl component, which binder isthought to cure by way of a Maillard reaction. However, such binderstend to be stiff and unsuitable for flexible substrates and cure tooslowly for practical application.

There remains a need for an inexpensive, formaldehyde-free, thermosetbinder from renewable materials that develops strength early in thecuring process. To solve the problem of providing renewable source rapidcuring thermosetting binders, the present inventors have sought toprovide a formaldehyde free binder of the present invention.

STATEMENT OF THE INVENTION

The present invention provides aqueous compositions which may functionas binders comprising one or more ammonium salt of an inorganic acid andat least one carbohydrate. Preferably, the carbohydrate is amonosaccharide or disaccharide. In a preferred embodiment, the aqueousbinder composition additionally comprises a Lewis acid catalyst. Morepreferably, the composition consists essentially of rapid curing bindersthat do not contain protein, peptide, amino acid, an ammonium salt of amonomeric or polymeric polycarboxylic acid, an ammonium salt of amonomeric or polymeric (poly)hydroxy(poly)carboxylic acid, orcombinations thereof.

The present invention provides aqueous compositions comprising, as apercentage by weight of solids: a) from 25% to 92% of one or morecarbohydrate chosen from the group consisting of: a monosaccharide, adisaccharide, a polysaccharide, a derivative thereof, and a combinationthereof; and b) at least 8% of one or more salt, which salt is anammonium salt of an inorganic acid.

In one embodiment, the monosaccharide, disaccharide, polysaccharide, orderivative thereof comprises at least 30% monosaccharide, disaccharide,or derivative thereof, or combination thereof. In another embodiment,the monosaccharide, disaccharide, polysaccharide, or derivative thereofcomprises at least 30% dextrose.

In yet another embodiment, the monosaccharide, disaccharide,polysaccharide, or derivative thereof comprises corn syrup comprising atleast 30% dextrose.

In a further embodiment, the ammonium salt of an inorganic acid isselected from the group consisting of: ammonium phosphate monobasic,(NH₄)H₂PO₄, ammonium phosphate dibasic, (NH₄)₂HPO₄, and a water solubleammonium polyphosphate.

In a different embodiment, the aqueous composition further comprises aLewis acid.

In still another embodiment, the aqueous composition further comprisesan emulsion polymer in an amount of from 5% to 50% by weight of polymersolids, as a percentage of total composition solids. In one suchembodiment, the emulsion polymer comprises, as polymerized units, one ormore multi-ethylenically unsaturated monomer.

In addition, the present invention provides methods of treatingsubstrates with the aqueous binder compositions, optionally followed byheat curing. Although the compositions may find use as binders evenwithout any curing, or after minimal cure, preferably, the compositionsare heated to provide a cured binder.

For each composition described herein, there exists an accompanyingembodiment in which the aqueous composition is a binder composition andin which the composition is present in a composite material or product.As defined herein, the term “composite material” refers to materialscomprising: (a) a substrate material selected from fibers, slivers,chips, particulate matter, films, sheets, and combinations thereof; and(b) the binder composition of the described embodiment.

Thus, in another aspect, the invention provides a composite materialcomprising: (a) a substrate material selected from fibers, slivers,chips, particulate matter, films, sheets, and combinations thereof; and(b) a cured binder composition derived from an aqueous compositioncomprising, as a percentage by weight of solids: (i) from 25% to 92% ofone or more carbohydrate chosen from the group consisting of: amonosaccharide, a disaccharide, a polysaccharide, a derivative thereof,and a combination thereof; and (ii) at least 8% of one or more salt,which salt is an ammonium salt of an inorganic acid.

In yet another aspect, the invention provides a composite materialcomprising: (a) a substrate material selected from fibers, slivers,chips, particulate matter, films, sheets, and combinations thereof; and(b) a cured binder composition derived from an aqueous compositioncomprising, as a percentage by weight of solids: (i) from 25% to 87% ofone or more carbohydrate chosen from the group consisting of: amonosaccharide, a disaccharide, a polysaccharide, or a derivativethereof; (ii) at least 8% of one or more salt, which salt is an ammoniumsalt of an inorganic acid; and (iii) from 5% to 50% of one or moreemulsion polymer.

In still another aspect, the invention provides a composite materialcomprising: (a) a substrate material selected from fibers, slivers,chips, particulate matter, films, sheets, and combinations thereof; and(b) one or more amino sugar, or derivative thereof. In one suchembodiment, the amino sugar is glucosamine.

As used herein, the phrase “alkyl” means any aliphatic alkyl grouphaving one or more carbon atoms, the alkyl group including n-alkyl,s-alkyl, i-alkyl, t-alkyl groups or cyclic aliphatics containing one ormore 5, 6 or seven member ring structures.

As used herein, the term “ammonium” includes, but is not limited to,⁺NH₄, ⁺NH₃R¹, ⁺NH₂R¹R², where R¹ and R² are each independently selectedin, and where R¹ and R² are selected from alkyl, cycloalkyl, alkenyl,cycloalkenyl, heterocyclyl, aryl, and heteroaryl. That is, the term“ammonium” includes “alkyl ammonium”.

As used herein, the phrase “aqueous” or “aqueous solvent” includes waterand mixtures composed substantially of water and water-misciblesolvents.

As used herein, “wt %” or “wt. percent” means weight percent based onsolids.

As used herein, the phrase “based on the total weight of binder solids”or “weight percent of the total solids in the binder” refers to weightamounts of any given ingredient in comparison to the total weight amountof all the non-water ingredients in the binder (e.g., carbohydrate(s),inorganic acid salt(s), Lewis acid salt(s), emulsion copolymer(s), andthe like). Binder compositions of this invention can be aqueous or dry(with water optionally added prior to application to a substrate).

As used herein, the term “polymer” includes the term “copolymer”, and,unless otherwise indicated, the term “copolymer” refers to polymers madefrom any two or more different monomers, including, for example,terpolymers, pentapolymers, homopolymers functionalized afterpolymerization so that two or more different functional groups arepresent in the product copolymer, block copolymers, segmentedcopolymers, graft copolymers, and any mixture or combination thereof.(Co)polymer means homopolymer or copolymer.

As used herein, the phrase “emulsion polymer” refers to a polymer thathas been prepared by emulsion polymerization.

As used herein, the phrase “formaldehyde-free composition” refers tocompositions substantially free from added formaldehyde, and which donot liberate substantial formaldehyde as a result of drying and/orcuring. Preferably, the binder or material that incorporates the binderliberates less than 10 ppm of formaldehyde, more preferably less than 1ppm of formaldehyde, as a result of drying and/or curing the binder (10ppm or 1 ppm based on the weight of sample being measured forformaldehyde release).

Unless otherwise indicated, any term containing parentheses refers,alternatively, to the whole term as if no parentheses were present andthe term without that contained in the parentheses, and combinations ofeach alternative. Thus, as used herein, the term “(meth)acrylate” meansacrylate, methacrylate, and mixtures thereof and the term“(meth)acrylic” used herein means acrylic, methacrylic, and mixturesthereof. Likewise, the term “(poly)saccharide” encompasses, in thealternative, polysaccharide, or the generic term “saccharide” (whichlatter may include a polysaccharide, a monosaccharide, or adisaccharide), or mixtures thereof.

As used herein, the phrases “(C₃-C₁₂)-” or “(C₃-C₆)-” and the like referto organic compounds or structural portions of organic compoundscontaining 3 to 12 carbon atoms and 3 to 6 carbon atoms, respectively.

The singular forms “a,” “an,” and “the” include plural referents unlessthe context clearly dictates otherwise. Unless defined otherwise,technical and scientific terms used herein have the same meaning as iscommonly understood by one skilled in the art. The endpoints of allranges directed to the same component or property are inclusive of theendpoint and independently combinable.

As used herein, unless otherwise indicated, the phrase “glass transitiontemperature” or “Tg” refers to a measured Tg, determined by differentialscanning calorimetry (DSC) using a heating rate of 10° C./minute, takingthe mid-point in the heat flow versus temperature transition as the Tgvalue.

Unless otherwise indicated, conditions of temperature and pressure areroom temperature and standard pressure, also referred to as “ambientconditions”. The compositions may be dried under conditions other thanambient conditions.

As used herein, unless otherwise indicated, the phrase “molecularweight” refers to the weight average molecular weight of a polymer asmeasured by gel permeation chromatography (GPC). Gel permeationchromatography, otherwise known as size exclusion chromatography,actually separates the members of a distribution of polymer chainsaccording to their hydrodynamic size in solution rather than their molarmass. The system is then calibrated with standards of known molecularweight and composition to correlate elution time with molecular weight.The techniques of GPC are discussed in detail in Modern Size ExclusionChromatography, W. W. Yau, J. J Kirkland, D. D. Bly; Wiley-Interscience,1979, and in A Guide to Materials Characterization and ChemicalAnalysis, J. P. Sibilia; VCH, 1988, p. 81-84.

The molecular weight information for a low molecular weight sample(e.g., 10,000) may be determined more accurately by techniques such asmass spectrometry or light scattering techniques as is known in the art.Herein, lower molecular weights, such as polysaccharides, are determinedby gel permeation chromatography with laser light scattering.

The aqueous binder composition of the present invention comprises atleast one carbohydrate. The term carbohydrate refers to polyhydroxylatedcompounds many of which contain aldehydic or ketonic groups or yieldsuch groups on hydrolysis. Simple carbohydrates are referred to assugars or saccharides. Sugars refer to monosaccharides, disaccharides,or polysaccharides, depending on the number of sugar units linkedtogether. Monosaccharides usually consist of five or six carbon atomsand are referred to as pentoses and hexoses, receptively. If themonosaccharide contains an aldehyde it is referred to as an aldose; ifit contains a ketone, it is referred to as a ketose. The aqueous bindercomposition may comprise one or more monosaccharide, or disaccharide, orpolysaccharide, or degradation product thereof. The carbohydratecomponent may be a monosaccharide in its aldose or ketose form,including a triose, a tetrose, a pentose, a hexose, or a heptose; or adisaccharide; or a polysaccharide; or combinations thereof.Glyceraldehyde and dihydroxyacetone are considered to be aldotriose andketotriose sugars, respectively. Examples of aldotetrose sugars includeerythrose and threose; and ketotetrose sugars include erythrulose.Aldopentose sugars include ribose, arabinose, xylose, and lyxose; andketopentose sugars include ribulose, arabulose, xylulose, and lyxulose.Examples of aldohexose sugars include glucose (for example, dextrose),mannose, galactose, allose, altrose, talose, gulose, and idose; andketohexose sugars include fructose, psicose, sorbose, and tagatose.Ketoheptose sugars include sedoheptulose. Other natural or syntheticstereoisomers or optical isomers of such carbohydrates may also beuseful as the carbohydrate component of the aqueous binder composition.Similarly, polysaccharides (including disaccharides) may find use in theaqueous binder compositions, for example, sucrose, lactose, maltose,starch, and cellulose. A number of powdered or granulated sugars orsugar syrups, including corn syrup, high fructose corn syrup, and thelike, may act as sources of the carbohydrate component of the aqueousbinder composition.

The carbohydrate component of the aqueous binder composition optionallymay be substituted, for example with hydroxy, halo, alkyl, alkoxy, orother substituent groups.

Higher molecular weight polysaccharides that may be useful in the binderof this invention include those selected from the group consisting ofstarch, cellulose, gums such as guar and xanthan, alginates, chitosan,pectin, gellan and modifications or derivatives thereof which areprovided by etherification, esterification, acid hydrolysis,dextrinization, oxidation or enzyme treatment. Such polysaccharides canbe derived from natural products, including plant, animal and microbialsources. Polysaccharide starches include maize or corn, waxy maize, highamylose maize, potato, tapioca and wheat starches. Other starchesinclude varieties of rice, waxy rice, pea, sago, oat, barley, rye,amaranth, sweet potato, and hybrid starches available from conventionalplant breeding, e.g., hybrid high amylose starches having amylosecontent of 40% or more, such as high amylose corn starch. Geneticallyengineered starches, such as high amylose potato and potato amylopectinstarches, may also be useful.

The polysaccharides may be modified or derivatized, such as byetherification, esterification, acid hydrolysis, dextrinization,oxidation or enzyme treatment (e.g., with alpha-amylase, beta-amylase,pullulanase, isoamylase, or glucoamylase), or bio-engineered.

The polysaccharide used in this inventive binder composition may have aweight average molecular weight of greater than 10,000, or greater than100,000 (e.g. as high as 1,000,000 or even as high as 10,000,000).However, lower molecular weight (poly)saccharides are preferred; the(poly)saccharide preferably has a weight average molecular weight ofless than 10,000, or, even, less than 1,000. In one embodiment, the(poly)saccharide preferably has a molecular weight of less than 500.Weight average molecular weight of the (poly)saccharide is measuredusing gel permeation chromatography with laser light scattering.

Thus, most preferably, the (poly)saccharide is a monosaccharide ordisaccharide. Dextrose has been found to be particularly suitable. Inone exemplary embodiment, a high dextrose content syrup (greater than30% dextrose) is used as the carbohydrate component. In such syrups, thehigher the dextrose content, the better; syrups with 97%, or greater,dextrose content are commercially available, for example ADM 97/71 cornsyrup, from Archer Daniels Midland Company (Decatur, Ill., USA).

Preferably, the carbohydrate should be sufficiently non-volatile tomaximize its ability to remain in the binder composition during theheating or curing thereof.

The (poly)saccharide may comprise from 25%, or from 50%, or from 60%, upto 92%, or up to 90%, by weight of solids as a percent of the totalsolids in the binder; preferably the (poly)saccharide comprises from70%, or from 75%, or from 80%, up to 90%, or up to 85%, or up to 80% byweight of solids as a percent of the total solids in the binder; andmost preferably from 75-85%, or 80-85%.

The aqueous binder composition comprises at least one ammonium salt ofan inorganic acid, for example, ammonium salts of sulfuric acid, ornitric acid, or hydrochloric acid, or phosphoric acid, or phosphorousacid among others. Such salts may be mono-basic, or dibasic, orpolybasic depending on the acid. For example, phosphoric acid (H₃PO₄)has potentially three acidic protons. Thus, for example, ammoniumphosphate monobasic, (NH₄)H₂PO₄, ammonium phosphate dibasic, (NH₄)₂HPO₄,and ammonium phosphate tribasic, (NH₄)₃PO₄, may find use in the bindercomposition of this invention. Mixed ammonium salts of phosphoric acidare also contemplated such as ammonium sodium phosphate, (NH₄)₂NaPO₄,and ammonium sodium hydrogen phosphate Na(NH₄)HPO₄; as well as ammoniumsalts of tungstic acid, such as ammonium tungstate, para and meta.Moreover, ammonium polyphosphate may also be used; preferably a watersoluble ammonium polyphosphate. Other suitable ammonium salts includeammonium nitrate, ammonium sulfate, and ammonium chloride. As discussedearlier, the term “ammonium” includes “alkyl ammonium”. Preferably, theaqueous binder composition is at an alkaline pH (a pH of 7 or higher),which minimizes corrosion of any mixing or storage or processingequipment. In one embodiment, the pH of the aqueous binder compositionis less than or equal to about 10.

The ammonium salt may be present at a level of 8-75 weight percent basedon solids as a percentage of the total solids in the binder. Preferably,the ammonium salt is present at a level of from 10%, or from 15%, up toa level of 50%, or up to 30%; and, most preferably, is at a level offrom 15% up to 20% based on solids as a percentage of the total solidsin the binder.

Lewis acids useful in the present invention include, but are not limitedto, titanates and zirconates such as organic titanates and zirconatessold by DuPont under the Trade name Tyzor, for example, but not limitedto, water soluble Tyzors such as Tyzor™ LA, Tyzor™ 131, Tyzor™ 217, andTyzor™ 218; dibutyltindilaurate, other organo-tin salts, inorganic tinsalts such as tin(IV) chloride and corresponding sulfates or nitrates;Al₂(SO₄)₃.xH₂O, MgCl₂.6H₂O, AlK(SO₄)₂.10H₂O, Al₂Zn(SO₄)₄, and Lewisacids having the formula MX_(n) wherein M is a metal, X is a halogenatom or an inorganic radical or anion (including polyatomic radicals oranions, such as sulfate, nitrate, and the like), and n is an integer offrom 1 to 5, such as BX₃, AlX₃, FeX₃, GaX₃, SbX₃, SnX₄, AsX₅, ZnX₂, andHgX₂. A combination of Lewis acid catalysts may also be used.Preferably, the Lewis acid is water soluble (having a solubility inwater of greater than 1 gram per liter). Preferably, the Lewis acidcatalyst is selected from the group consisting of: sulfates, nitrates,halides, citrates, lactates, and gluconates of zinc, aluminum,zirconium, iron, magnesium, tin, titanium and boron; and their mixedmetal salts; organo-tin compounds or salts; and titanates or zirconatesof alcohols or (poly)carboxylic acids.

The Lewis acid may be present at a level of 2-15 weight percent based onsolids as a percentage of the total solids in the binder. Preferably,the Lewis acid is present at a level of from 3%, or from 5%, up to alevel of 15%, or up to 12%, or up to 6%; and, most preferably, is at alevel of from 5% up to 10% based on solids as a percentage of the totalsolids in the binder.

Carbohydrate-based binders, when cured, may find use, for example, inmineral wool applications such as fiberglass and stonewool insulation,and acoustic panels. For other applications, such as where rigid bindersare unsuitable, for example, in thin fiberglass or polyester mats thatare to be used in roofing, the mat is held together with a binder, suchas a latex (co)polymer, that allows the mat to flex substantially afterthe binder is cured, to allow the mat to be processed further (e.g., toconvert mat into roofing material), and allow the end product containingthe mat to flex well in use. For example, in roofing mat, the endroofing product may be impregnated or layered with asphaltic materials,and the resultant roofing product retains flexibility to allow it toconform to the roof (e.g., bend over peaks and into valleys), and toallow the roofing material to expand and contract with temperaturefluctuations, without the mat itself fracturing because it is toobrittle and lacks flexibility. Other applications where curable,formaldehyde-free binders that are “flexible” are useful in this regardinclude paper, cellulosics, polyester, glass mat, and glass veil. Suchsubstrates are used in a variety of applications, including flooringunderlayments, filtration media, and building products.

In one embodiment of the invention, the aqueous binder compositionadditionally comprises an aqueous emulsion copolymer to provide greaterflexibility and elasticity to both the binder and the cured thermosetproduct. The emulsion copolymer used in the binder of this embodiment ofthe invention may include, as copolymerized units, a carboxy monomerbearing a carboxylic acid group, anhydride group, or salt thereof orhydroxyl-group, such as (meth)acrylic acid andhydroxyethyl(meth)acrylate. For example, the emulsion copolymer may be ahigh acid polymer, a low acid polymer, or it may not comprise any acidmonomer, depending on the desired property balance of the resultingbinder. For example, a high acid polymer may comprise from 5% to 40%, or5% to 30%, or 10% to 20%, by weight based on the weight of the emulsioncopolymer solids, of the carboxy monomer bearing a carboxylic acidgroup, anhydride group, or salt thereof, such as (meth)acrylic acid; alow acid polymer may comprise from 1% to 5%, or 1% to 3%, by weightbased on the weight of the emulsion copolymer solids, of the carboxymonomer bearing a carboxylic acid group, anhydride group, or saltthereof. Ethylenically unsaturated carboxylic acid monomers include, forexample, methacrylic acid, acrylic acid, crotonic acid, fumaric acid,maleic acid, 2-methyl maleic acid, itaconic acid, 2-methyl itaconicacid, a,b-methylene glutaric acid, monoalkyl maleates, and monoalkylfumarates; ethylenically unsaturated anhydrides such as, for example,maleic anhydride, itaconic anhydride, acrylic anhydride, and methacrylicanhydride; and salts thereof. Acrylic acid is the preferred carboxymonomer.

Ethylenically unsaturated co-monomers useful in the emulsion copolymerinclude (meth)acrylic ester monomers such as methyl (meth)acrylate,ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate,decyl (meth)acrylate, isodecyl (meth)acrylate, hydroxyethyl(meth)acrylate, and hydroxypropyl (meth)acrylate; (meth)acrylamide orsubstituted (meth)acrylamides; styrene or substituted styrenes;butadiene; vinyl acetate or other vinyl esters; acrylonitrile ormethacrylonitrile; and the like. Styrene-acrylic latexes or all-acryliclatexes have been found to be well-suited to the performancerequirements of the targeted end products.

In one embodiment, the latex emulsion copolymer of this inventioncomprises one or more copolymerized multi-ethylenically unsaturatedmonomers such as, for example, allyl methacrylate (ALMA), allylacrylate, diallyl phthalate, 1,4-butylene glycol dimethacrylate,1,2-ethylene glycol dimethacrylate, 1,6-hexanediol diacrylate,butadiene, trimethylolpropane triacrylate (TMPTA) and divinyl benzene.Of these, ALMA, divinylbenzene (DVB), diallyl phthalate, 1,4-butyleneglycol dimethacrylate, and 1,6-hexanediol diacrylate are preferred. ALMAis the most preferred. The multi-ethylenically unsaturated monomer canbe effectively employed at levels as low as 0.1%, by weight based on theweight of the copolymer, preferably from 0.1 to 10%, or 0.1 to 5%, morepreferably from 0.1 to 4%, or 0.2 to 4%, and most preferably from 0.1 to2%, or 0.2 to 2%, or 0.25 to 2%, or 1.0 to 2%, by weight based on theweight of the copolymer.

Chain transfer agents such as mercaptans, polymercaptans, and halogencompounds can be used in the polymerization mixture in order to moderatethe molecular weight of the copolymer composition. Generally, from 0% to10% by weight, based on the weight of the emulsion copolymer, of C₄-C₂₀alkyl mercaptans, mercaptopropionic acid, or esters of mercaptopropionicacid, can be used. Preferably, the emulsion copolymer used in thisinvention has a Tg of from 0-35° C., preferably 5-20° C., fornon-treated substrates having an inherent elongation of greater than 5%,such as spunbond polyester; and from 35-70° C. for non-treatedsubstrates having an inherent elongation of less than 5%, such as glassmat, as measured by differential scanning calorimetry per ASTM 3418/82,midpoint temperature; cell calibration using an indium reference fortemperature and enthalpy.

The emulsion copolymer used in this invention has weight averagemolecular weight of from 5,000 to 2,000,000, preferably from 20,000 to1,000,000. For applications requiring high performance at elevatedtemperatures, the emulsion copolymer most preferably has a weightaverage molecular weight of 100,000 to 1,000,000, however, for some roomtemperature applications, the molecular weight is most preferably from30,000 to 600,000.

The emulsion polymer may be present in the composition in an amount offrom 5%, or from 10%, up to 80%, or up to 50%, or up to 30% by weight ofsolids as a percent of the total weight of solids in the binder,preferably from 10% to 25%, or, most preferably, from 10% to 20%.

In a preferred embodiment suitable for rigid binders, the aqueous bindercomposition comprises approximately 75-85% by weight, based on the totalweight of binder solids, of a saccharide such as dextrose, andapproximately 15-25% of an ammonium salt of an inorganic acid, such asammonium phosphate monobasic, (NH₄)H₂PO₄, or dibasic, (NH₄)₂HPO₄. In aparticularly preferred embodiment, the composition further comprises aLewis acid catalyst, such as zinc sulfate, in an amount of approximately5-10 wt. %, based on the total weight of solids of the other componentsof the composition.

In a preferred embodiment suitable for flexible binders, the aqueousbinder composition further comprises approximately 10-20% by weight,based on the total weight of binder solids, of an acrylic or styreneacrylic emulsion polymer.

The binder of this invention can contain, in addition, conventionaltreatment components such as, for example, emulsifiers; pigments;fillers or extenders, such as clays and talcs; anti-migration aids;curing agents; coalescents; surfactants, particularly nonionicsurfactants; spreading agents; mineral oil dust suppressing agents;biocides; plasticizers; organosilanes; anti-foaming agents such asdimethicones and emulsified poly(dimethicones), silicone oils andethoxylated nonionics; corrosion inhibitors, such as thioureas,oxalates, and chromates; colorants; antistatic agents; lubricants;waxes; anti-oxidants; coupling agents such as silanes, particularlySilquest™ A-187 (manufactured by GE Silicones-OSi Specialties, locatedin Wilton Conn.); other amino silanes; epoxy silanes, vinyl silanes andhydrophobic silanes. Other additives may include polymers not of thepresent invention; and waterproofing agents such as silicones andemulsion polymers, particularly hydrophobic emulsion polymerscontaining, as copolymerized units, greater than 30% by weight, based onthe weight of the emulsion polymer solids, ethylenically-unsaturatedacrylic monomer containing a C5 or greater alkyl group.

Additionally, this invention includes methods for treating substratescomprising: Forming the wet, uncured web of fibers, and preferablytransferred to a moving screen running through a binder applicationstation where the aqueous binder of the invention is applied to the mat.The binder can be applied to the structure by any suitable meansincluding, for example, air or airless spraying, padding, saturating,roll coating, curtain coating, beater deposition, coagulation or dip andsqueeze application, and the resultant saturated wet bindered web layingon a supporting wire or screen is run over one or more vacuum boxes toremove enough binder to achieve the desired binder content in the mat.The binder level in the inventive mats can range from 5 or from 10 to 35wt. percent of the finished dry mat, preferably 12 to 30 wt. percent andmost preferably from 15 to 25 wt. percent, such as 20+/−3 wt. percent.The binder composition is curable by the application of heat, i.e., thebinder composition is a thermosetting composition.

The binders of this invention are useful to bind non-woven webs, amongother things. “Non-woven web(s)” refers to any article or sheet-likeform made from natural and/or synthetic fibers wherein the fibers arealigned in a random or semi-random order (i.e., not deliberatelyordered). One skilled in the art understands that formation of someorder occurs during the web forming process (primarily in the machinedirection); however, this is completely different from the orderingobtained from traditional weaving or knitting processes. Suitable fibersfor use in forming the web include, but are not limited to, fiberglass,cellulose, modified cellulose (cellulose acetate), cotton, polyesters,rayon, polyacrylonitrile (PAN), polylactic acid (PLA), polycaprolactone(PCL), polyolefins and bi-component fiber comprising two or morefiber-forming polymers such as polypropylene and polyethyleneterephthalate and the like. Included in the definition of non-woven webssuitable for use with this invention are porous films prepared by theaction of chemical or mechanical processing (e.g., apertured films).Also included as useful for the purpose of this invention are paper andpaper products. The present invention will find utility with any weightof non-woven web and will depend greatly on the requirements of theparticular application. Manufacturing processes for making non-wovenwebs are well known in the art. These include, for example, wet-laid,air-laid (dry laid), spunbond, spunlace, meltblown and needle punch.Particularly suitable webs will have a base weight (i.e., the weight ofthe web before any coating or treatments are applied) of less than 100grams per square meter (gsm). In another aspect the webs will have abase weight of less than 20 gsm.

The composition components need not all be pre-mixed prior toapplication of the binder to the substrate. For example, one or morecomponents may be applied to a non-woven substrate, followed byapplication of the other binder components of this invention either inaqueous or dried form. After application, the binder can be cured byheating the coated non-woven to a sufficient temperature where it cureson the substrate.

Preferably, the binder compositions are formaldehyde-free. To minimizethe formaldehyde content of the aqueous composition, it is preferred,when preparing a polymer-containing formaldehyde-free curablecomposition, to use polymerization adjuncts and additives such as, forexample, initiators, reducing agents, chain transfer agents, curingagents, biocides, surfactants, emulsifiers, coupling agents,anti-foaming agents, dust suppressing agents, fillers and the like,which are themselves free from formaldehyde, do not generateformaldehyde during the polymerization process, and do not generate oremit formaldehyde during the treatment of heat-resistant nonwovens.

In drying (if applied in aqueous form) and curing the curablecompositions, the duration, and temperature of heating, will affect therate of drying, ease of processing or handling, and property developmentof the treated substrate. Suitable heat treatment at 100° C. or more,and up to 400° C., may be maintained for from 3 seconds to 15 minutes.Preferably, heat treatment temperatures range 150° C. or higher; suchpreferred heat treatment temperatures may range up to 225° C., or, morepreferably, up to 200° C. or, up to 150° C. Where the substrate containswood, temperatures of 100° C. to 220° C., are preferred.

Drying and curing can be done in two or more distinct steps, if desired.For example, the curable composition can be first heated at temperaturesand for times sufficient to at least partially dry, but not fully curethe composition, followed by heating for a second time, at highertemperatures and/or for longer periods of time, to effect curing. Suchprocedures, referred to as “B-staging,” can be used to providebinder-treated nonwovens, for example, in roll form, which can be curedlater, with or without forming or molding into a particularconfiguration, concurrent with the curing process.

Suitable substrates include, for example, heat-sensitive substrates,such as wood, including, solid wood, wood particles, fibers, chips,flour, pulp, and flakes; paper and cardboard; textiles, includingcotton, linen, wool, and synthetic textiles from polyester, rayon, ornylon, and superabsorbent fibers; vegetable fibers, such as jute, sisal,flax, cotton and animal fibers; as well as heat resistant substrates,such as metal; plastic; fibers, such as glass and mineral fibers, aramidfibers, ceramic fibers, metal fibers, carbon fibers, polyimide fibers,and woven and non-woven fabrics made therefrom. Heat-resistantnon-wovens may also contain fibers which are not in themselvesheat-resistant such as, for example, polyester fibers, rayon fibers,nylon fibers, and superabsorbent fibers, in so far as or in amounts suchthat they do not materially adversely affect the performance of thesubstrate.

Non-woven fabrics are composed of fibers which can be consolidated inwhole or in part by mechanical means such as, for example, byentanglement caused by needle-punching, by an air-laid process, and by awet-laid process; by chemical means such as, for example, treatment witha polymeric binder; or by a combination of mechanical and chemical meansbefore, during, or after nonwoven fabric formation. Some non-wovenfabrics are used at temperatures higher than ambient temperature suchas, for example, glass fiber-containing non-woven fabrics which areimpregnated with a hot asphaltic composition pursuant to making roofingshingles or roll roofing material. When a non-woven fabric is contactedwith a hot asphaltic composition at temperatures of from 150° C. to 250°C., the non-woven fabric can sag, shrink, or otherwise become distorted.Therefore, non-woven fabrics which incorporate a curable compositionshould substantially retain the properties contributed by the curedaqueous composition such as, for example, tensile strength. In addition,the cured composition should not substantially detract from essentialnon-woven fabric characteristics, as would be the case, for example, ifthe cured composition were too rigid or brittle or became sticky underprocessing conditions.

EXAMPLES

These examples serve to illustrate the invention, outlining specificbinder compositions of this invention and ones that compare to suchcompositions. The scope of the invention is not intended to be limitedby these examples. The preparations and test procedures are carried outat room temperature and standard pressure unless otherwise indicated.

Reagents/Abbreviations:

Dextrose monohydrate, CAS#5996-10-1 (Dex)

Lactose, CAS#63-42-3.

Citric acid, CAS#77-92-9 (CA)

Ammonium hydroxide 28-30%, CAS#1336-21-6, NH₃.H₂O

Ammonium sulfate, CAS#7783-20-2, (NH₄)₂SO₄

Ammonium phosphate monobasic, CAS#7722-76-1, (NH₄)H₂PO₄

Ammonium phosphate dibasic, CAS#7783-28-0, (NH₄)HPO₄

Ammonium nitrate, CAS#6484-52-2, (NH₄)NO₃

Sodium phosphate dibasic, CAS#7558-79-4, Na₂HPO₄

Zinc sulfate heptahydrate, CAS#7446-20-0, ZnSO₄.7H₂O

Tyzor® LA (DuPont Company, Wilmington, Del., USA)

Hydroxylamine Hydrochloride, CAS#5470-11-1, (NH₄)OH

D-Glucosamine, CAS#29031-19-4

Example 1 Treated Glass Microfiber Filter Paper and Tensile TestingThereof

Aqueous curable formulations were prepared as shown in Table 1. Glassmicrofiber filter paper sheets (20.3×25.4 cm, Cat No. 1820 866, WhatmanInternational Ltd., Maidstone, England) were weighed, dip-coated by handthrough a trough, placed between two pieces of cardboard, and runthrough a roll padder at a speed and pressure such that the add-on wasapproximately 15 weight % binder. The add-on of the coated sheets wasdetermined as the cured binder weight as a percentage of filter paperweight. Each sheet was dried in a Mathis oven set to 90° C. for 90seconds and cured in another Mathis oven at specified times andtemperature.

The cured sheets were cut into fourteen 1 inch (cross machine direction)by 4 inch (machine direction) strips and tested for tensile strength inthe machine direction in a Thwing-Albert EJA Vantage Universal tensiletester. The fixture gap was 2 inches and the pull rate was 2inches/minute and the sensitivity was 10 lb. Both the dry and hot-wettensile data reported is the average peak force measured during testingof seven test strips. Strips were tested either “as is” (dry tensile) orimmediately after a 30 minute soak in water at 85° C. Table 2 presentshot-wet tensile data and Table 4 presents the percent tensile retentionwhich is defined as the (hot-wet tensile/dry tensile)×100%, as oftenreported in the industry.

Example 2 Early Strength Development of Thermoset Compositions

Table 1, below, presents the formulation components, in grams, for somerepresentative aqueous binder compositions of the invention.

TABLE 1 Formulation components, in grams (g.), excluding waterAdditional Sample Dex (g.) CA (g.) NH₃•H₂0 (g.) components (g.) Comp. A120.00 — — — Comp. A2 15.00 2.73 2.42 — Comp. A3 20.00 6.00 Na₂HPO₄ Comp.A4 20.00 5.2 Tyzor ™ LA Ex. A1 20.00 — — 6.00 (NH₄)₂SO₄ Ex. A2 20.00 — —6.00 (NH₄)H₂PO₄ Ex. A3 20.00 — — 6.00 (NH₄)₂SO₄ + 4.63 ZnSO₄ Ex. A420.00 6.00 (NH₄)₂HPO₄ + 5.2 Tyzor ™ LA Ex. A5 — — — 23.0 ADM 36/43 CornSyrup¹ + 6.00 (NH₄)H₂PO₄ Ex. A6 — — — 23.0 ADM 97/71 Corn Syrup¹ + 6.00(NH₄)₂HPO₄ Ex. A7 20.00 3.0 (NH₄)₂HPO₄ Ex. A8 20.00 1.5 (NH₄)₂HPO₄ Comp.A5 20.00 — — 1.10 (NH₄)H₂PO₄ ¹Corn Syrup is ADM 36/43 (Archer DanielsMidland Company, Decatur, Illinois, USA), comprises 36% dextrose and hasa solids content of 80%. 2. Tyzor ™ LA (DuPont Chemicals, Wilmington,DE, USA), a Titanate of lactic acid; supplied as a 50% solids solution.

For each sample, inventive examples Ex. A1-8 and comparative examplesComp. A1-A5, the formulation components were simply admixed in aqueoussolution using a benchtop stirrer. The binder was applied and cured onglass microfiber filter paper sheets as described in Example 1 (above),and then tested for hot wet tensile properties (Table 2, below). Thebinder add-on was approximately 15%. Binders based on sugars often haveacceptable dry tensile strength properties, however, the soluble natureof the sugars invariably compromises the hot wet tensile properties ofthese systems, which properties are considered important.

TABLE 2 Hot Wet Tensile (lb.) after curing at 190° C. Sample 30 sec.cure 60 sec. cure Comp. A1 0 0 Comp. A2 0 1.5 Comp. A3 0 0 Comp. A4 0 0Ex. A1 2.6 2.3 Ex. A2 6.4 5.6 Ex. A3 4.7 5.0 Ex. A4 4.4 5.7 Ex. A5 0 2.2Ex. A6 4.2 4.1 Ex. A7 3.0 3.7 Ex. A8 0 2.5 Comp. A5 0 0

The data in Table 2 indicate that the formulations comprisingsaccharides and ammonium salts of inorganic acids (for example, Ex. A1and Ex. A2) cure faster and have greater mechanical strength than aformulation comprising a saccharide and the ammonium salt of an organicacid, such as citric acid (see, for example, Comp. A2). Addition of aLewis acid, such as zinc sulfate, can further improve the speed of cureand resulting strength (see, for example, Ex. A3 versus Ex. A1).

Sample Comp. A5 shows that the use of a smaller quantity (˜6%) ofammonium phosphate monobasic in the binder composition fails to producea cured product with any significant tensile strength. It appears thatthe ammonium salt of the inorganic acid does not function as a catalyst.

Not shown in the table, the kinetics of the cure was also followed byDynamic Mechanical Analysis (DMA). The extent of crosslinking wasevaluated by DMA (from 30° C. to 250° C., increments of 4° C./min). Thecrosslinking reaction (and thus curing) occurs during the rise intemperature, which is manifested by a significant increase in thedynamic storage tensile modulus, E′ (see, for example, L. E. Nielsen andR. F. Landel, Mechanical Properties of Polymers and Composites, 2ndedn., Marcel Dekker, 1994). Thus, the DMA plots of Modulus, E′ (GPa) vs.Temperature (° C.) showed a marked upward slope starting at thetemperature corresponding to the onset of cure, and moving to a newmaximum, taken as the final cure temperature. Comparative compositionComp. A2 (dextrose+citric acid+ammonium hydroxide) shows an onsettemperature of 152° C. and a final cure at 170° C. On the other hand,the inventive compositions of dextrose with ammonium phosphate monobasic(33%), or with ammonium phosphate dibasic (16%), both show an onsettemperature of approximately 137° C. and a final cure temperature atapproximately 152° C., showing that cure can be achieved earlier and atlower energy consumption for the inventive compositions.

Further examples of aqueous binder formulations illustrative of theinvention are shown in Table 3.

TABLE 3 Formulation components in grams (g.), excluding water AdditionalDesignation DEX (g.) CA (g.) NH₃•H₂0 (g.) Components (g.) Comp. B1 110.020.0 17.7 — Comp. B2 — — — 20.0 Lactose Ex. B1 20.0 — — 6.0 (NH₄)H₂PO₄.Ex. B2 20.0 — — 6.0 (NH₄)₂HPO₄. Ex. B3 6.0 (NH₄)H₂PO₄ + 20.0 Lactose Ex.B4 20.0 — — 6.0 (NH₄)H₂PO₄ + 5.2 Tyzor ® LA Ex. B5 20.0 — — 6.0(NH₄)H₂PO₄ + 2.5 Al(NO₃)₃•9H₂O

Table 4 lists the percent tensile retention, which is defined as the(hot-wet tensile/dry tensile)×100%, for cured sheets with these binderformulations (15% binder add-on).

TABLE 4 Percent Tensile Retention Designation % Tensile Retention (30sec. cure at 190° C.) Comp. B1 0 Comp. B2 0 Ex. B1 28 Ex. B2 32 Ex. B324 Ex. B4 52 Ex. B5 37

Table 4, similarly to Table 2, shows that formulations comprisingsaccharides and ammonium salts of inorganic acids (samples, Ex. B1-B5)display better early cure and development of mechanical strength than aformulation comprising a saccharide and the ammonium salt of an organicacid comprising carboxylic acid groups (see, for example, Comp. B1).Moreover, a Lewis acid accelerates the cure and improves the mechanicalproperties of formulations comprising a saccharide and the ammonium saltof an inorganic acid, as shown, for example, by comparison of Ex. B4 andEx. B2.

Example 3 Evaluation of Amino Sugars as Thermosetting Binders

This Example explores the use of commercially available glucosaminesulfate as a thermosetting binder. It also explores the use of dextroseplus hydroxylamine as a thermosetting binder. Representativeformulations are shown in Table 5, below.

TABLE 5 Formulations, in grams (g), excluding water Glucosamine sulfateSample DEX (Mw = 228.2) CA NH₄OH ZnSO₄•7H₂O (NH₄)₂SO₄ Other Comp. C120.0 — — — Comp. C2 20.0 3.5 NH₂OH•HCl Comp. C3 20.0 3.6 0.9 Ex. C1 20.0Ex. C2 20.0 2.5 6.0 Ex. C3 25.0 7.4 (NH₄)NO₃ Ex. C4 20.0 — — 4.6 6.0

The binder compositions were applied and cured on glass microfiberfilter paper sheets as described in Example 1 (above); the add-on wasapproximately 15%.

The hot wet tensile tests (Table 6, below) were performed as describedin Example 1, except the cured sheets were cut into 1 inch (crossmachine direction) by 5 inch (machine direction) strips and tested fortensile strength in the machine direction in a Thwing-Albert EJA VantageUniversal tensile tester. The fixture gap was 3 inches, the jawseparation rate was 1 in/min, and the sensitivity was 20 lb.

TABLE 6 Hot-Wet Tensile Strength (lb/in) of Treated Glass Filter PaperHot-Wet 90 sec/90 C. dry + Tensile Strength (lbf) Sample 190 C. cure(30, 60, or 180 sec) 30 sec 60 sec 180 sec Comp. C1 Dextrose 0.0 0.0 0.0Comp. C2 Dextrose with Hydroxylamine- 0.0 0.0 0.2 HCl Comp. C3Dextrose + Citric Acid & 0.0 0.5 6.8 Ammonium Hydroxide Ex. C1Glucosamine Sulfate 0.0 0.2 4.2 Ex. C2 Glucosamine Sulfate with 0.0 1.23.1 ZnSO4 + (NH4)2SO4 Ex. C3 Dextrose + Ammonium Nitrate 1.2 2.9 4.2 Ex.C4 Dextrose + (NH4)2SO4 + 4.7 5.0 4.8 ZnSO4

In sample Comp. C2, dextrose is reacted with hydroxylamine, but the wettensile strength is poor under the current set of dry/cure conditions.Sample Ex. C1 shows that an amino sugar such as glucosamine can bedirectly used as a thermosetting binder. As for Example 2, above, theaddition of an ammonium salt of an inorganic acid (ammonium sulfate) anda Lewis acid (zinc sulfate) appears to accelerate the cure (see SampleEx. C2) in these systems.

Table 7 shows the retained tensile strength for these formulations (15%binder add-on). Separate experiments explored the use of ammoniumlignosulfonate as a reactant with dextrose (with and without, the Lewisacid, zinc sulfate). Although these systems show good dry tensilestrengths, the performance was lacking with respect to hot wet tensilestrength.

TABLE 7 % Retained Tensile Strength (wet/dry) of Treated Glass FilterPaper % Retained 90 sec/90 C. dry + Strength (wet/dry) Sample 190 C.cure (30, 60, or 180 sec) 30 sec 60 sec 180 sec Comp. C1 Dextrose 0 0 0Comp. C2 Dextrose with Hydroxylamine- 0 0 2 HCl Comp. C3 Dextrose +Citric Acid & 0 5 39 Ammonium Hydroxide Ex. C1 Glucosamine Sulfate 0 234 Ex. C2 Glucosamine Sulfate with 0 12 28 ZnSO4 + (NH4)2SO4 Ex. C3Dextrose + Ammonium Nitrate 9 21 36 Ex. C4 Dextrose + (NH4)2SO4 + ZnSO4

Example 4 Strength and Flexibility of Thermoset Compositions

The thermoset compositions of this example were formulated as describedabove, additionally admixing a latex emulsion polymer at 10% and 20%levels (based on weight of solids; polymer solids as a percentage ofsolids content of the other composition components). The compositionswere applied to fiber glass mats (Table 9), or polyester spunbond mats(Table 10) and cured as described earlier. The emulsion polymers wereprepared as follows:

Synthesis of Emulsion Copolymer A

After heating 340 g deionized water and 5.0 g sodium lauryl sulfate (28%Solids) to 90° C., 2.4% of a monomer mixture of 199 g water, 7.5 gsodium lauryl sulfate (28%), 349 g methyl methacrylate, 100 g butylacrylate, 2.28 g allyl methacrylate and 4.55 g acrylamide is addedfollowed by 5.2 g ammonium persulfate solution (27.3% solids). Thiscombination is held at 88° C. for 5 minutes. Then, the remaining monomermix is added gradually along with 19.7 g of a 1.6% aqueous ammoniumpersulfate solution. The reaction mixture is cooled to 70° C. and 2.0 gof an iron sulfate solution (0.26% solids) is added. While at 70° C., 13g of a 13.4% aqueous t-butyl hydroperoxide solution and 26 g of a 3.8%aqueous solution of hydroxymethane sulfonic acid monosodium salt aregradually added, and then the mixture is further cooled to 40° C. andaqueous ammonia is added to adjust pH to 8.5. The product is filteredthrough 100 and 325 mesh screens.

Synthesis of Emulsion Copolymers B, C, and D

A 5-liter round-bottom flask equipped with a paddle stirrer,thermocouple, nitrogen inlet, and reflux condenser was charged with876.4 grams of deionized water, 24.2 grams of sodium hypophosphitemonohydrate, 28.5 grams of a sodium lauryl ether sulfate surfactantsolution (30%), 3.1 grams of sodium hydroxide, and 0.058 grams of aninhibitor. The mixture was heated to 88° C.

For each polymer synthesis, a monomer emulsion was prepared using 459.7grams of deionized water, 89.2 grams of a sodium lauryl ether sulfatesurfactant solution (30%), 553.9 grams of butyl acrylate, 969.7 grams ofstyrene, and 268.9 grams of acrylic acid. A 97.0 gram aliquot of thismonomer emulsion was added to the reaction flask, with stirring,followed by a solution of 7.4 grams of ammonium persulfate dissolved in33.3 grams of deionized water. After an exotherm and while maintaining areaction temperature of 85° C., the monomer emulsion and a separatesolution of 7.4 grams of ammonium persulfate in 156.9 grams of deionizedwater were gradually added over a total time of 130 minutes. After theseadditions were complete a solution of 42.6 grams of sodium hydroxidedissolved in 397.4 grams deionized water was added. A solution of 0.022grams of ferrous sulfate heptahydrate in 4.8 grams deionized water and asolution of 0.022 grams of ethylene diamine tetraacetate, tetra sodiumsalt, dissolved in 4.8 grams of deionized water was added to thereaction mixture. A solution of 7.9 grams of aqueoustert-butylhydroperoxide (70%) diluted with 31.2 grams deionized waterand a solution of 5.3 grams of sodium bisulfite dissolved in 62.8 gramsof deionized water were gradually added to the reaction mixture. After a15 minute hold, a solution of 7.9 grams of aqueoustert-butylhydroperoxide (70%) diluted with 31.2 grams deionized waterand a solution of 5.3 grams of sodium bisulfite dissolved in 62.8 gramsof deionized water were gradually added to the reaction mixture. After a15 minute hold, 47.6 grams of deionized water was added, and thereaction mixture was cooled to room temperature. When the reactionmixture was cool below 40° C., a biocide was added and the latex wasfiltered through a 100 mesh sieve. Emulsion polymers B, C, and Dfollowed this procedure, but with the monomer emulsions prepared asshown in Table 8.

The resulting latexes had a solids content of roughly 46.0%. Theemulsion copolymers B, C, and D had Tg (DSC): 55° C., 10° C., and 10°C., respectively.

TABLE 8 Monomer Emulsion Recipes for Emulsion Polymers B, C, and DEmulsion Emulsion Emulsion Polymer B (g.) Polymer C (g.) Polymer D (g.)Deionized water 459.7 456.8 456.8 Sodium lauryl ether 89.2 88.7 88.7sulfate surfactant (30%) Butyl acrylate 553.9 1072.3 1072.3 Styrene969.7 423.9 637.6 Acrylic acid 268.9 267.2 53.4 Allyl methacrylate 0.017.8 17.8

Amino resins, such as urea formaldehyde (UF) resins, are well known andwidely commercially available. They are formed, for example, from thereaction of urea and formaldehyde to form compounds containing methylolgroups, which subsequently under the application of heat, with orwithout catalysts, react further, or condense, or cure to form polymers.The methylol groups in the resin are known to react with active hydrogengroups such as other methylol groups to form ether or methylene groupsthereby forming polymeric structures. Rhoplex™ GL-618 and Rhoplex™ HA-8(both from Rohm and Haas Company, Philadelphia, USA) are commerciallyavailable acrylic emulsion polymers that contain methylolacrylamide toprovide sites for crosslinking to such amino resin binders.

Tables 9 and 10, below, show the mechanical properties of thesesaccharide thermoset compositions comprising an emulsion polymer.

Glass Mat Preparation Procedure and Test Procedures

To prepare the glass mats used in the samples in Table 9, glass fibernon-woven handsheets are prepared with Johns Manville 137 Standard, 3.2cm (1¼ inch) length, sized glass chop using approximately 7.6 grams ofglass fiber per sheet (0.82 kg per 9.3 square meters; 1.8 pounds per 100square feet). The glass fiber is dispersed in water using SUPERFLOC™A-1883 RS (Cytec Industries Incorporated, West Paterson, N.J., USA), ananionic polyacrylamide water-in-oil emulsion, and RHODAMEEN™ VP-532 SPB(Rhodia Chemical Company, Cranbury, N.J., USA), an ethoxylated fattyamine cationic dispersing agent. Handsheets are formed in a Williams(Williams Apparatus Company, Watertown, N.Y., USA) handsheet mold. Thewet sheets are transferred to a vacuum station and de-watered. In eachcase, the aqueous binder composition is applied to a de-watered sheetand the excess is vacuumed off. The sheets are dried/cured in a forcedair oven for 2½ minutes at 200° C. The binder amount on the samples is17% LOI (loss on ignition).

Determination of LOI (Loss On Ignition)

A 6.4 cm by 7.6 cm (2.5 inch by 3 inch) piece of dried/cured fiberglassmat was cut. The sample was weighed and then placed in a muffle furnaceat 650° C. for 2 minutes. The sample was removed and then reweighed. %LOI was calculated using the equation:% LOI=(wt. before burning−wt. after burning)×100/(wt. before burning).Tensile Strength Testing

Handsheets are cut into 2.54 cm by 12.7 cm (1 inch by 5 inch) strips fortensile testing and cut for tear testing. Tensile testing is performedon seven strips from each sample using a Thwing-Albert EJA VantageUniversal tensile tester (Thwing-Albert Instrument Co., West Berlin,N.J., USA) with a 90.7 kg (200 lb.) cell, 2.54 cm/min (1 inch/min) jawspeed, 20% sensitivity, and a 7.6 cm (3 inch) gap. Dry tensile isperformed on the prepared strips. All tensile values are reported inpounds force (lbf).

Elmendorf Tear Strength Testing

Elmendorf tear strength is determined on cut samples of dried/curedhandsheet which are 6.4 cm by 7.6 cm (2.5 inches by 3 inches). A singleply sample is placed in a Thwing-Albert Tear Tester with a 1600 g teararm. The sample is notched with a 1.9 cm (0.75 inch) cut and the arm isreleased. The tear strength is recorded in grams (grams force).

Formulation for Polymer Modified Binders

The formulations for the samples presented in Table 9 were prepared asdescribed earlier; Comp. D1 uses the addition of 175.0 grams, g., (159.1g. dry weight) dextrose, 381.6 g. water, 28.9 g. citric acid, and 25.5g. (7.7 g. dry weight) ammonium hydroxide; further examples in Table 9use 150.0 g. (136.3 g. dry weight) dextrose, 400.8 g. water, 40.9 g.ammonium phosphate, (plus 17.7 g. zinc sulfate, if present), followed byaddition of either 10% or 20% by weight of emulsion polymer (if present)based on polymer solids as a percentage of the total weight of solids ofthe other components in the formulation.

TABLE 9 Mechanical properties of saccharide thermoset compositionscomprising an emulsion polymer on fiber glass mat¹ Hot-Wet Tensile TearStrength Sample Formulation Strength (lbf) (grams-f) Ex. D1 Dex +(NH₄)H₂PO₄ 14.9 292 Ex. D2 Dex + (NH₄)H₂PO₄ + 8.9 490 ZnSO₄ Ex. D3 Dex +(NH₄)H₂PO₄ + 14.3 438 10% Polymer A Ex. D4 Dex + (NH₄)H₂PO₄ + 13.3 623ZnSO₄ + 10% Polymer A Ex. D5 Dex + (NH₄)H₂PO₄ + 20.5 444 20% Polymer AEx. D6 Dex + (NH₄)H₂PO₄ + 5.5 402 20% Polymer B Comp. D1 Dex + NH₄Citrate 19.1 333 Comp. D2 UF Resin 21.2 498 ¹Binder add-on isapproximately 17%.

The data in Table 9 show that addition of 10% or 20% emulsion polymercan favorably impact the balance of properties in these saccharidebinder systems, although in some cases there may be a trade-off inperformance attributes.

Polyester Spunbond Mat Preparation and Test Procedures

More flexible systems are tested on polyester spunbond mat. Commercialpolyester spunbond mat (non-treated) is cut into 15″×12″ sheets. Sheetsare dip coated in test binder formulation at 11% bath solids (byweight). Soaked sheets are padded at 40 psi and then immediately curedat 200° C. for 3 minutes. Binder add-on: 20% by weight.

Room Temperature Testing: Tensile Strength, Elongation for PolyesterSpunbond Mat

An Instron 4201 tensile tester equipped with a 1 kN load cell was usedfor room temperature (RT) tensile strength and elongation.

For RT tensile strength and RT elongation, a cured sheet was cut into1½″×10″ strips. Strips were tested by placing them in the jaws of thetensile tester and pulled apart at a crosshead speed of 8 inches/minutewith a 6″ gap. The maximum RT tensile strength is measured, andexpressed in pounds force (lbf). Elongation (strain) is measured atmaximum RT tensile strength, and expressed as %.

TABLE 10 Effect of addition of emulsion polymer on saccharide thermosetproperties¹ Dextrose + Dextrose + (NH₄)H₂PO₄ ³ (NH₄)₂SO₄ + ZnSO₄ ³ RT %RT % Latex Modifier² Tensile (lbf) Elongation Tensile (lbf) ElongationNone 81.2 42 76.5 41 Polymer C 83.9 46 89.4 45 Polymer D 91.0 51 90.7 50GL-618 91.1 45 84.8 43 HA-8 87.8 55 90.7 57 ¹On spunbond polyester mat(flexible substrate); binder add-on is approximately 20%. ²Latexmodifier is added at a level of 10% by weight of solids as a percentageof total solids of other binder components. ³Formulations ratios are asdescribed for the samples shown in Table 9.

The data in Table 10 show that addition of 10% emulsion polymer (polymersolids as a percentage of other composition component solids) can showimprovement in both room temperature tensile strength and % elongationproperties. These inventive compositions thus provide an inexpensive,formaldehyde-free, thermoset binder that retains both flexibility andstrength after cure. The inventive compositions derive primarily fromrenewable resources as opposed to petroleum feedstocks.

1. An aqueous formaldehyde free composition comprising, as a percentageby weight of solids: a. from 25% to 92% of one or more carbohydratechosen from the group consisting of: a monosaccharide, a disaccharide, apolysaccharide, a derivative thereof, and a combination thereof; b. atleast 8% of one or more salt, which salt is an ammonium salt of aninorganic acid; and further comprising an emulsion polymer in an amountof from 5% to 50%, the emulsion copolymer chosen from a high acidpolymer of from 4 to 40 wt. % based on copolymer solids, of acopolymerized carboxy monomer, a low acid polymer, and a polymercomprising a copolymerized multi-ethylenically unsaturated monomer. 2.The aqueous composition of claim 1 wherein the monosaccharide,disaccharide, polysaccharide, or derivative thereof comprises at least30% monosaccharide, disaccharide, or derivative thereof, or combinationthereof.
 3. The aqueous composition of claim 1 wherein themonosaccharide, disaccharide, polysaccharide, or derivative thereofcomprises at least 30% dextrose.
 4. The aqueous composition of claim 1wherein the ammonium salt of an inorganic acid is selected from thegroup consisting of: ammonium phosphate monobasic, (NH₄)H₂PO₄, ammoniumphosphate dibasic, (NH₄)₂HPO₄, and a water soluble ammoniumpolyphosphate.
 5. The aqueous composition of claim 1 further comprisinga Lewis acid.
 6. The aqueous composition of any one of claims 1 to 5,wherein the emulsion polymer is chosen from a high acid polymer.
 7. Theaqueous composition of claim 1 wherein the emulsion polymer comprises,as polymerized units, one or more multi-ethylenically unsaturatedmonomer.
 8. A composite material comprising: (a) a substrate materialselected from fibers, slivers, chips, particulate matter, andcombinations thereof; and (b) a cured binder composition derived from anaqueous formaldehyde free composition comprising, as a percentage byweight of solids: i. from 25% to 87% of one or more carbohydrate chosenfrom the group consisting of: a monosaccharide, a disaccharide, apolysaccharide, or a derivative thereof; ii. at least 8% of one or moresalt, which salt is an ammonium salt of an inorganic acid; and iii. from5% to 50% of one or more emulsion polymer chosen from a high acidpolymer of from 4 to 40 wt. % based on copolymer solids, of acopolymerized carboxy monomer, a low acid polymer and a polymercomprising a copolymerized multi-ethylenically unsaturated monomer. 9.An aqueous formaldehyde free composition comprising, as a percentage byweight of solids: a. from 25% to 92% of one or more carbohydrate chosenfrom the group consisting of: a monosaccharide, a disaccharide, apolysaccharide, a derivative thereof, and a combination thereof; and b.at least 8% of one or more salt, which salt is an ammonium salt of aninorganic acid; and, further comprising a Lewis acid chosen fromtitanates and zirconates, organo-tin salts, inorganic tin salts,MgCl₂.6H₂O, AlK(SO₄)₂, 10H₂O, and Al₂Zn(SO₄)₄.
 10. The aqueouscomposition as claimed in claim 9 wherein the Lewis acid is chosen fromtitanates and zirconates.
 11. A composite material comprising: (a) aheat resistant substrate material selected from fibers, slivers, chips,particulate matter, and combinations thereof; and (b) a cured bindercomposition derived from an aqueous formaldehyde free compositioncomprising, as a percentage by weight of solids: i. from 25% to 92% ofone or more carbohydrate chosen from the group consisting of: amonosaccharide, a disaccharide, a polysaccharide, or a derivativethereof; ii. at least 8% of one or more salt, which salt is an ammoniumsalt of an inorganic acid; and iii. further comprising a Lewis Acid. 12.The composite material as claimed in claim 11, wherein the substratematerial comprises fibers, or woven or non-woven fabrics made fromfibers.